Anaerobic reduction of glycerol to propanediol-1.3 by Lactobacillus brevis and Lactobacillus buchneri

Three strains of Lactobacillus brevis and one strain of Lactobacillus buchneri grew very poorly on glucose. Good growth was observed on glucose plus glycerol; while glucose was fermented to acetate or ethanol, lactate and CO2, glycerol was dehydrated to 3-hydroxy-propanal and subsequently reduced to propanediol-1.3. Cell extracts of L.brevis and L.buchneri grown on glucose plus glycerol contained a B12-dependent glycerol dehydratase and a propanediol-1.3 dehydrogenase. Glycerol was not metabolized when used as the only substrate. Fructose as sole carbon source was partially reduced to mannitol. The joint fermentation of fructose and glycerol yielded propanediol-1.3 from glycerol. Ribose was fermented but did not support glycerol fermentation. Extracts from ribose grown cells did not contain glycerol dehydratase or propanediol-1.3 dehydrogenase. Besides glycerol the following diols were metabolized as cosubstrates with glucose: propanediol-1.2, ethylene glycol and butanediol-2.3 yieldin g propanol-1, ethanol and butanol-2 respectively. Washed cells of two L.brevis strains, B 18 and B 20, formed propanediol-1.3 and propanediol-1.2 from glycerol, the third strain B 22 formed only propanediol-1.2 from glycerol in the absence of glucose. (IFU)